An intracranial hematoma is a collection of blood within the skull. It's usually caused by a blood vessel that bursts in the brain. It may also be caused by trauma such as a car accident or fall. The blood may collect in the brain tissue or underneath the skull, pressing on the brain.

Some head injuries, such as one that causes only a short period of unconsciousness, can be minor. However, an intracranial hematoma is potentially life-threatening. It usually requires immediate treatment. This might include surgery to remove the blood.


You might develop signs and symptoms of an intracranial hematoma right after a head injury, or they may take weeks or longer to appear. You might seem fine after a head injury. This period is called the lucid interval.

Over time, pressure on your brain increases, producing some or all of the following signs and symptoms:

  • Headache that gets worse
  • Vomiting
  • Drowsiness and progressive loss of consciousness
  • Dizziness
  • Confusion
  • Unequal pupil size
  • Slurred speech
  • Loss of movement (paralysis) on the opposite side of the body from the head injury

As more blood fills your brain or the narrow space between your brain and skull, other signs and symptoms may appear, such as:

  • Lethargy
  • Seizures
  • Unconsciousness

When to see a doctor

An intracranial hematoma can be life-threatening, requiring emergency treatment.

Seek immediate medical attention after a blow to the head if you:

  • Lose consciousness
  • Have a persistent headache
  • Experience vomiting, weakness, blurred vision, unsteadiness

If you don't notice signs and symptoms right after you've been hit in the head, watch for physical, mental and emotional changes. For example, if someone seems fine after a head injury and can talk but later becomes unconscious, seek immediate medical care.

And even if you feel fine, ask someone to watch out for you. Memory loss after a blow to your head can make you forget about the blow. Someone you tell might be more likely to recognize the warning signs and get you medical attention.


A head injury is the most common cause of bleeding within the skull. A head injury may result from motor vehicle or bicycle accidents, falls, assaults, and sports injuries.

If you're an older adult, even mild head trauma can cause a hematoma. This is especially true if you're taking a blood-thinning medication or an anti-platelet drug, such as aspirin.

You can have a serious injury even if there's no open wound, bruise or other obvious damage.

There are three categories of hematoma — subdural hematoma, epidural hematoma and intracerebral (intraparenchymal) hematoma.

Subdural hematoma

This occurs when blood vessels burst between your brain and the outermost of three protective layers that cover your brain (dura mater). The leaking blood forms a hematoma that presses on the brain tissue. A hematoma that gets bigger can cause gradual loss of consciousness and possibly death.

The three types of subdural hematomas are:

  • Acute. This most dangerous type is generally caused by a severe head injury, and signs and symptoms usually appear immediately.
  • Subacute. Signs and symptoms take time to develop, sometimes days or weeks after the injury.
  • Chronic. The result of less severe head injuries, this type of hematoma can cause slow bleeding, and symptoms can take weeks and even months to appear. You might not remember hurting your head. For example, bumping your head while getting into the car can cause bleeding, especially if you're on blood-thinning medication.

All three types require medical attention as soon as signs and symptoms appear so that permanent brain damage can be prevented.

The risk of subdural hematoma increases as you age. The risk is also greater for people who:

  • Take aspirin or other blood-thinning medication daily
  • Misuse alcohol

Epidural hematoma

Also called an extradural hematoma, this type occurs when a blood vessel bursts between the outer surface of the dura mater and the skull. Blood then leaks between the dura mater and the skull to form a mass that presses on brain tissue. The most common cause of an epidural hematoma is trauma.

Some people with this type of injury remain conscious, but most become drowsy or go into a coma from the moment of trauma. An epidural hematoma that affects an artery in your brain can be deadly without prompt treatment.

Intracerebral (intraparenchymal) hematoma

This type of hematoma, also known as intraparenchymal hematoma, occurs when blood pools in the tissues of the brain. There are many causes, including trauma, rupture of a bulging blood vessel (aneurysm), poorly connected arteries and veins from birth, high blood pressure, and tumors. Diseases can cause spontaneous leakage of blood into the brain. A head trauma can result in multiple severe intracerebral hematomas.


To prevent or minimize head injury:

  • Wear a helmet and make sure your kids wear helmets. Wear an appropriate and properly fitted helmet when playing contact sports, bicycling, motorcycling, skiing, horseback riding, skating, skateboarding, snowboarding or doing any activity that could result in head injury.
  • Buckle your seat belt and make sure your kids are buckled in. Do so every time you drive or ride in a motor vehicle.
  • Protect young children. Always use properly fitted car seats, pad countertops and edges of tables, block stairways, attach heavy furniture or appliances to the wall to prevent tipping, and keep children from climbing on unsafe or unsteady objects. Place safety gates on stairs and guards on windows.

June 17, 2022
  1. Traumatic brain injury: Hope through research. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Hope-Through-Research/Traumatic-Brain-Injury-Hope-Through. Accessed May 13, 2022.
  2. Traumatic brain injury. Merck Manual Professional Version. http://www.merckmanuals.com/professional/injuries-poisoning/traumatic-brain-injury-tbi/traumatic-brain-injury. Accessed May 13, 2022.
  3. McBride W. Subdural hematoma in adults: Etiology, clinical features and diagnosis. https://www.uptodate.com/contents/search. Accessed May 13, 2022.
  4. McBride W. Subdural hematoma in adults: Management and prognosis. https://www.uptodate.com/contents/search. Accessed May 13, 2022.
  5. Karibe H, et al. Surgical management of traumatic acute subdural hematoma in adults: A review. Neurologia Medico-Chirurgica. 2014; doi:10.2176/nmc.cr.2014-0204.
  6. McBride W. Intracranial epidural hematoma in adults. https://www.uptodate.com/contents/search. Accessed May 18, 2022.
  7. Bydon M (expert opinion). Mayo Clinic. May 18, 2022.
  8. Ferri FF. Traumatic brain injury. In: Ferri's Clinical Advisor 2022. Elsevier; 2022. https://www.clinicalkey.com. Accessed May 18, 2022.